Hi Lei, I believe you're seeing issue with the latest version of Cython (0.21) that has been fixed in the development version. See https://bitbucket.org/yt_analysis/yt/pull-request/1202/ You can check what version of Cython you are using with this command: python -c 'import Cython; print Cython.__version__' If it is 0.21, I suggest removing the string "language=extension.language," from line 106 of setup.py and that should fix your problem. Douglas Rudd Scientific Computing Consultant Research Computing Center drudd@uchicago.edu<mailto:drudd@uchicago.edu> On Sep 22, 2014, at 12:06 AM, Lei Yang <yangleiseti@gmail.com<mailto:yangleiseti@gmail.com>> wrote: Dear yt-users, I was trying to install yt using pip on my mac, but I got an error massage “ValueError: got unexpected compilation option: language”, and "Command python setup.py egg_info failed with error code 1 in /private/var/folders/t0/7w97r14x7z3cm9kf1s9jq0mh0000gn/T/pip_build_leiyang/yt “. I have no idea what’s going on there. Would you please give me some tips to figure this out? Thanks so much!!! Lei _______________________________________________ yt-users mailing list yt-users@lists.spacepope.org<mailto:yt-users@lists.spacepope.org> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org